Celiac disease and non-celiac gluten sensitivity are a part of gluten-related disorders. Gluten and gluten alike proteins are found in wheat, rye, barley and oats. Celiac disease is an autoimmune disorder that develops in genetically predisposed individuals after gluten consumption. Typical symptoms are diarrhea with or without steatorrhea, weight loss and failure to thrive. A combination of serology and endoscopy with biopsy and pathohistological analysis is used to establish the diagnosis. Pathohistological findings characteristic of celiac disease are villous atrophy, crypt hyperplasia and increased density of intraepithelial lymphocytes. Currently, the only available treatment is strict adherence to a gluten-free diet. Refractory celiac disease is a form of celiac disease characterized by persisting symptoms despite adhering to the gluten-free diet for at least 12 months. Two types of refractory celiac disease are recognized, type I and type II, which is also considered pre-lymphoma due to a high risk of transformation into enteropathy-associated T cell lymphoma. Non-celiac gluten sensitivity (NCGS) presents with similar symptoms as celiac disease. Due to the lack of sensitive and specific biomarkers, establishing a clear NCGS diagnosis is difficult. As with celiac disease, the only available treatment is strict adherence to a gluten-free diet.